A tunnel

ABSTRACT

A tunnel 2 for the in-line anti-bacterial treatment of plucked poultry carcasses (or other animal carcasses) with a liquid cryogen or a cold gas at a temperature of less than 0° C. has an entrance 18 and an exit 20 for the poultry carcasses. A monorail conveyor 22 extends from the entrance 18 to the exit 20 and passes thorough the tunnel 2. Poultry suspension shackles 24 are able to pass along the conveyor 22. Thus, poultry carcasses are able to be conveyed through the tunnel 2. The conveyor 22 may follow a path which reverses direction at least once.

This invention relates to a tunnel for the in line, anti-bacterialtreatment of plucked poultry carcasses with a liquid cryogen and/or acold gas.

When live poultry arrive at a processing plant, they are typicallyshackled at the ends of their legs and then conveyed in line through asequence of stations at which they are stunned, humanely slaughtered,exsanguinated, scalded to soften the attachment of the feathers, pluckedto remove the feathers, feet removed, decapitated, eviscerated, andwashed. The resulting poultry carcasses are chilled.

Food-borne pathogens represent a significant and serious threat to humanhealth. Numerous species of micro-organism reside naturally on manytypes of food. Some of these micro-organisms are capable of causingdiseases in man upon ingestion. Sensible precautions, such as thoroughcooling at an appropriate temperature, observation of correct storageprotocols for raw and uncooked food, and adhering to proper hygienestandards when handling food, can all reduce but not eliminate incidenceof such disease.

Among the disease-causing pathogens, Campylobacter is the most commonbacterial cause of food poisoning. Campylobacter infection is extremelycommon in retail poultry. It is believed that transfer of Campylobacterbacteria to the skin occurs when the birds are slaughtered andeviscerated.

There is therefore a need for improved treatment of poultry carcasses.It has been reported that surface-borne micro-organisms can be destroyedby being subjected to a temperature below 0° C. WO 2004/080189Adiscloses a method comprising of rapidly cooling meat by exposure to arapid cooling temperature of no more than about minus 10° C. forsufficient time to provide a frozen crust on the meat and chilling theresultant crust-frozen meat by exposure of said crust-frozen meat to achilling temperature greater than the cooling temperature but no morethan about plus 10° C. to raise the temperature of the surface of themeat and to maintain said surface at a temperature no higher than thefreezing temperature of the meat for at least sufficient time to injurelethally or kill bacteria, is used to reduce the viability of bacteriaon meat. The method is stated to have particular application in theprocessing of poultry meat to kill bacteria.

It is recognised in WO 2004/080189A that the process described thereinwould preferably be mechanised for processing continuous lines of meat,e.g. poultry birds. it is stated that in preferred embodiments, theinvention would be applied to an existing meat processing line and ifmeans for rapidly cooling the meat were required, a rapid cooler wouldpreferably be retrofitted to an existing chiller. Moreover, it isdisclosed that in preferred embodiments the meat is rapidly chilled bymechanical refrigeration to produce crust frozen meat.

There remains however a need for practical equipment that is able to beincorporated into a poultry meat line without adversely affectingupstream or downstream processing of the poultry while enablingCampylobacter bacteria on the surface to be destroyed.

According to the present invention there is provided a tunnel for thein-line anti-bacterial treatment of plucked poultry carcasses (or otheranimal carcasses) with a cryogenic liquid and/or cold gas at atemperature below 0° C., the tunnel having an entrance and an exit forthe carcasses and a monorail conveyor extending through the tunnel fromthe entrance to the exit, along which poultry (or other animal)suspension shackles are able to pass in use.

The tunnel of the present invention allows a Campylobacter treatmentmethod to be carried out in an in-line poultry (or other anima)processing plant.

The conveyor may preferably reverse direction at least once. For a givenresidence time at a constant line speed, the configuration of theconveyor enables the length of the tunnel according to the invention tobe less than it would have to be were the conveyor to follow arectilinear path which does not reverse direction. Preferably, the saidconveyor reverses direction at least twice. Accordingly, the length ofthe tunnel is in the order of one third of what it would need to be werethe path to extend simply in a straight line from entrance to exit. Inconsequence, there are likely to be less practical difficulties inaccommodating the tunnel according to the invention in a commercialpoultry processing line. The conveyor any alternatively follow a wavypath, preferably with shallow curves. This arrangement may be useful forshortening the length of the tunnel and changing the orientation of thecarcasses as they pass through the tunnel.

In order to supply the tunnel with cryogenic liquid and/or cold gas, thetunnel preferably has in it an array of nozzles for spraying a cryogenicliquid into the tunnel. The cryogenic liquid naturally vaporises so asto create a cold gas. A cryogenic liquid is one that boils at atemperature below minus 100° C. at a pressure of 1 bar. A typicalcryogenic liquid for use in the tunnel according to the invention isliquid nitrogen or liquid air.

A tunnel according to the invention typically has in it a plurality offans for moving cryogenic liquid mist and cold gas within the tunnel.There are various options for the fans. In one option, at least some ofthe fans direct gas laterally relative to the path taken by the poultrycarcasses through the tunnel if desired, such fans may be impingementfans, that is fans which cause the cryogenic liquid mist and/or cold gasto impinge upon the carcasses. The nozzles may be arranged to directdroplets of cryogenic liquid at the poultry carcasses such that thecryogenic liquid droplets impinge upon the carcass. The nozzles mayalternatively or additionally be arranged to introduce droplets ofcryogenic liquid into the cold gas being directed at the poultrycarcasses such that the cryogenic liquid has the opportunity to vaporisebefore it impinges the carcasses,

In one embodiment of a tunnel according to the invention each length ofthe path followed in use by the poultry carcasses has a row of spraynozzles associated with it. All the nozzles may point in the samedirection.

A tunnel according to the invention typically has at least one outletport for the extraction of gas from the tunnel. The said outlet port istypically operationally associated with an extraction fan, typicallylocated in an extraction duct externally of the tunnel. The extractionfan or fans are typically operable to create a sub-atmospheric pressurein the tunnel so as to prevent or keep down loss of cold gas from thetunnel. In addition, a tunnel according to the invention typically has adoor to permit access for the purposes of cleaning the tunnel.

In one preferred embodiment, the tunnel is arranged to provide atreatment and at least one of a pre-treatment and/or a post-treatment,wherein the tunnel is arranged to provide the treatment along a portionof the path along which the carcasses move in use, and wherein thetunnel is arranged to provide the pre and/or post treatment alonganother portion of the path along which the carcasses move in use.Preferably, the tunnel is arranged to provide a pre-treatment, atreatment and a post-treatment in sequence.

In another aspect, the invention provides an apparatus for handlingcarcasses of poultry (or other animals), the apparatus comprising: atunnel according to any one of claims 1 to 14; a pre-treatment tunnellocated upstream of the tunnel; and a post-treatment tunnel locateddownstream of the tunnel, wherein both the pre-treatment tunnel and thepost-treatment tunnel comprise an entrance and an exit for the carcassesand a monorail conveyor extending from the entrance to the exit, alongwhich poultry (or other animal) suspension shackles are able to pass inuse. The pre and post treatment tunnels are preferably arranged to besupplied with developed gas and/or liquid cryogen from the tunnel.

By providing pre and/or post treatment stages in the tunnel itself, orby means of pre and/or post treatment tunnels, the overall chillingtreatment of the carcasses can be managed and designed to provide asynergistic chilling process which makes the best use of the liquidcryogen cold gas already being used in the treatment.

The invention further provides a tunnel or apparatus as described abovewhen located at least partially within the chiller of a poultry (orother animal) processing plant. Preferably, the said tunnel or apparatusis arranged to supply developed gas from the tunnel to the chiller, orto a heat exchanger located within the chiller. The developed gas maycome from any one of the tunnel and/or the pre/post treatment tunnels ifpresent.

A tunnel and apparatus according to the invention will now be describedby way of example with reference to the accompanying drawings, in which:

FIG. 1 is a schematic perspective view of a cooling tunnel for thetreatment of poultry carcasses;

FIG. 2 is a side view of the tunnel shown in FIG. 1; and;

FIG. 3 is a plan view of the tunnel shown in FIG. 1, but with the roofremoved.

The drawings are schematic and have been simplified to aid understandingof the invention. For example, the monorail conveyor and shacklearrangement are illustrated only in FIG. 2; the fan blades are not shownin any of FIGS. 1 to 3; and means for supplying the cryogenic liquid tothe spray bars are omitted from all the drawings.

Referring to the drawings, a tunnel 2 stands on legs 4, which may beprovided with adjustable feet (not shown) so as to assist in installingthe tunnel 2 such that its floor is truly horizontal. The tunnel 2 has afloor 6 and a roof 8; a pair of end wails 10 and 12; and a pair of sidewalls 14 and 16. An entrance 18 for poultry carcasses is formed in theend wall 10 and a complementary exit 20 for poultry carcasses from thetunnel 2 is formed in the end wall 12. Although not shown in thedrawings, the floor 6, roof 8, end walls 10 and 12 and side walls 14 and16 are all thermally insulated. In a typical embodiment, each of theaforementioned walls, floor and roof is formed of a double-walledstructure, thermal insulation being located between the double walls.

As shown in FIG. 2, the tunnel 2 is associated with a monorail conveyor22 of a conventional kind in poultry carcass handling installations. Theconveyor 22 is able to advance shackles 24 from which the poultrycarcasses are suspended by their legs along a chosen path. The monorailconveyor 22 enters the tunnel 2 via entrance 18 and exits the tunnel 2via exit 20. The monorail conveyor 22 is located in the tunnel 2proximate the roof 8. Any suitable path shape and/or run trajectory maybe used for the monorail conveyor 22. For example, the path may bestraight or U-shaped or S-shaped to increase the amount of time that thecarcasses spend passing through the tunnel 2, or to allow the length ofthe tunnel 2 to be reduced without shortening the amount of time thatthe carcasses spend passing through the tunnel.

The tunnel 2 is provided with means for subjecting the poultry carcassesto temperatures below 0° C. Such treatment has previously been reported(for example in WO2004/080189 A1) to have an anti-bacterial effect,particularly in respect of Campylobacter bacteria. Accordingly, poultrycarcasses 26 are contacted with cryogenic liquid mist (comprisingcryogenic liquid droplets) and/or cold gas as they pass from theentrance 18 of the tunnel 2 to the exit 20. The cryogenic liquid mistand/or cold gas is created by spraying a liquid cryogen, typicallyliquid nitrogen or liquid air, for example, into the tunnel 2. For thesake of simplicity, for the remainder of this description liquidnitrogen will be used as an illustrative example of a liquid cryogen.However, it is to be understood that any suitable liquid cryogen may beused in place of liquid nitrogen.

Liquid nitrogen is introduced into the tunnel 2 as a fine mist via aplurality of spray nozzles 46 (FIG. 3). Depending on the treatmentmethod being used, the nozzles 46 may either arranged to direct theliquid nitrogen directly at the carcasses so that the droplets of liquidnitrogen impinge on the carcasses, or they may be arranged so that theliquid nitrogen has the opportunity to vaporise to form a cold gasbefore impinging on the carcasses. In the case where the nozzles 46 arearranged to direct the liquid nitrogen to impinge directly on thecarcasses, there will be some vaporisation of the liquid nitrogen beforeit so impinges. Liquid nitrogen which has impinged on the carcasses willalso vaporise. The nitrogen vapour, whether formed by direct impingementon the carcasses or not, spreads and/or circulate within the tunnel 2 toform a cold gas atmosphere (typically −196° to 170° representative). Ifdesired, some of the nozzles 46 may be arranged to direct the liquidnitrogen at the carcasses for direct impingement, while others may bearranged so that the liquid nitrogen has the opportunity to vaporisebefore impingement with the carcasses. If desired, the nozzles 46 in theupstream portion of the tunnel 2 may be arranged to direct the liquidnitrogen at the carcasses for direct impingement, and nozzles 46 in thedownstream portion of the tunnel 2 may be arranged to allow the liquidnitrogen to vaporise before impingement with the carcasses. Thisarrangement may be reversed if desired. Alternatively, the operation anddirection of the nozzles 46 may vary along the length of the tunnel 2 asdesired.

In the example shown in FIG. 3, the tunnel 2 is provided with spray bars40 depending from the roof 8. Each of the spray bars 40 is provided witha row of spray nozzles 46. As shown in FIG. 3, all the spray nozzles 46face poultry carcasses for the time being in the tunnel 2. It isbeneficial to direct the liquid nitrogen/nitrogen gas at both sides ofthe carcass as this helps to ensure that any hidden areas of thecarcass, such as neck flaps, are exposed to the liquid nitrogen/nitrogengas.

In operation, droplets of liquid nitrogen are ejected from the nozzles46 in the form of a spray or fine mist. Fans 48 are provided through theside was 14 and 16 of the tunnel 2 in order to circulate the liquidnitrogen mist and cold nitrogen gas and to direct it towards thecarcasses being conveyed through the tunnel 2. Typically, the fans areof the type that cause turbulence, and may also create so large avelocity as to cause energetic impingement of the liquid nitrogen mistand cold nitrogen gas on the poultry carcasses. In operation, a staticboundary layer of cold gas tends to form around the carcasses in thetunnel 2. For impingement to occur, the flow of cold gas or mist needsto have sufficient velocity to penetrate the static boundary layer. Ifdesired, additional or alternative fans (not shown) may be employed tocreate relatively high velocity jets of nitrogen mist/gas which retaintheir velocity as they impinge against the poultry carcasses. The liquidnitrogen is supplied to the spray bars 40 from a thermally-insulatedstorage vessel (not shown) conveniently located near to the tunnel 2 viaappropriately thermally-insulated piping (not shown) which hasterminations in inlets 47 to the spray bars 40. The operating pressureof the storage vessel is typically about 3 bar gauge for liquidnitrogen.

In one arrangement of fans (not shown) a “false” wail is provided atboth side walls 14 and 16 of the tunnel. Both false walls are providedwith a plurality of ports, each port being associated with animpingement fan. The impingement fans are positioned between thenegative false walls and side walls 14, 16 and are arranged so as todirect flows of gas through the ports at the carcasses. The spacesbetween a false wall and the negative side wall can serve as a passagefor gas to the fans, and a suitable gap may be left between the floor ofthe tunnel and the bottom of each false wall.

Tunnel 2 is typically provided with a first outlet port 51 near theentrance 18 for spent nitrogen mist/gas and a second outlet port 52 nearthe exit 20 for such mist/gas. The ports 51 and 52 are typically formednear the top of the &de walls 14 and 16 respectively. The ports 51 and52 communicate with an exhaust duct 54 (see FIG. 1) which is able tolead the nitrogen to a location where it can be safely discharged to theatmosphere without causing any hazard to human life or re-used inanother process. If desired, the exhaust duct may have a fan (not shown)located in it so as to assist in the withdrawal of nitrogen gas from thetunnel 2. This exhaust fan is typically set to operate at a speed so asto maintain a (small) subatmospheric pressure in the tunnel to avoid anynitrogen spilling out of the tunnel through the entrance 18 or the exit20, The operation of such exhaust fans is well known in the art ofcryogenic freezing tunnels.

The tunnel 2 is typically provided with a doors (not shown) in the endwalls 10, 12 so as to permit ready access to the interior to the tunnel2 for the purposes of routine and regular cleaning.

The tunnel 2 shown in the drawings may have dimensions selected for thetreatment of the carcasses of a particular species or genus of poultry,for example, the carcasses of chickens or turkeys.

The rate at which the carcasses are conveyed through the tunnel 2 isdetermined by the operation of the poultry line. As is well known in theart, such a poultry line is required to transport poultry, at firstlive, to stations at which the birds are, in sequence, stunned, humanelyslaughtered, exsanguinated, scalded to soften the attachment of thefeathers, plucked to remove the feathers, decapitated, eviscerated, andwashed. After washing, the birds are conveyed to a chiller such as ablast chiller or refrigerator in which they are held in chilled state.The tunnel 2 according to the invention may be located either downstreamof the chiller or, more preferably, within the chiller itself.

It is believed that the step of evisceration can cause the spread ofharmful bacteria such as Campylobacter to the external surfaces of theplucked birds. Washing is found not to be fully effective in removingthe bacteria. As previously mentioned, subjection of the carcasses totemperatures below 0° C. has an anti-bacterial effect. The tunnel 2therefore has to be operated so as to give the carcasses an adequateexposure to the liquid nitrogen mist/cold nitrogen gas. A minimumexposure time is typically in the order of five to sixty secondsdepending on the size of the carcass. Typically, the birds are conveyedat a line speed in the order of 20 to 50 metres per minute or more insome cases. The desired residence time of the birds in the gas dictatesthe path length followed by the carcasses. For example, if the residencetime in the tunnel 2 is one minute and the line speed is 50 metres perminute, a path length of 50 metres is required. By providing an S-shapedmonorail conveyor 22, with three straight runs and two U-bends forexample, the overall length of the tunnel 2 can generally be kept belowabout 20 metres. For a residence time of 20 seconds at a line speed of27 metres per minute, a path length of 9 metres is required. Byproviding a U-shaped monorail conveyor 22, the overall length of thetunnel 2 can generally be kept below about 5 metres. In the case of aU-shaped monorail conveyor 22, the entrance 18 and exit 20 may belocated in the same end wall.

The rate of introduction of the cryogenic liquid into the tunnel may beadjusted to give the desired tunnel operating temperature. A typicaltunnel operating temperature might be below minus 80° C. Preferably, thetunnel operating temperature will be in the range minus 170° C. to minus196° C. The tunnel operating temperature will typically be measured by atemperature probe located somewhere within the tunnel 2. It will beunderstood by those skilled in the art that the temperature measured mythe temperature probe will be representative only of the overalloperating temperature within the tunnel and that the temperaturedistribution within the tunnel will vary depending on proximity to thenozzles 46, proximity to the carcasses and position along the length ofthe tunnel 2. The operating parameters of the tunnel are preferably setby means of a desired tunnel operating temperature and the temperatureof the incoming liquid cryogen. A typical driving pressure for theliquid cryogen will be in the region of about 1 to 3.5 bar gauge. Asmentioned above, for liquid nitrogen, the liquid will be supplied to thenozzles 46 at about 3 bar gauge.

It will be appreciated from the drawings that the width of the tunnel isappreciably less than its length. One criterion affecting the width ofthe tunnel 2 is the desirability of maintaining a suitable separationdistance between the nozzles 46 and the poultry carcasses in operationof the tunnel 2. This is so as to avoid unnecessary freezing of thecarcass meat itself. It is preferred to create a sub-zero temperature atthe external surfaces of the carcasses, so as to damage fatallyCampylobacter bacteria thereupon, without freezing the poultry meatbeneath the surface. The reason for this preference is twofold. First,the freezing of the muscle meat is unnecessary so far as theanti-bacterial treatment of the poultry is concerned and thereforerepresents a wastage of the refrigeration contained in the cryogenicliquid that is sprayed into the tunnel 2. Secondly, freezing the meatreduces the value of the carcasses, at least in the EU, where, oncefrozen, poultry meat if subsequently thawed, is not permitted to be soldas fresh. The rate at which liquid nitrogen or other cryogenic liquid isintroduced into the tunnel and the speed at which the fans are operatedcan be determined by simple experiment so as to create the desiredexternal surface temperature on each carcass at its exit from the tunnel2 while keeping down the consumption of liquid nitrogen or othercryogenic liquid.

The apparatus according to the invention may be adapted to thatanti-bacterially the carcasses of animals other than poultry, forexample, the carcasses of pigs.

In another embodiment of the invention, the treatment equipment mayinclude zonal treatment areas. In one example, the tunnel 2 may belocated between an upstream pre-treatment tunnel (not shown) and adownstream post-treatment tunnel (not shown). The pre and post treatmenttunnels will each have an entrance, an exit and a section of themonorail conveyor 22 running through them for allowing the passage ofshackles carrying poultry (or other animal) carcasses generally asdescribed above for tunnel 2. The monorail conveyor 22 and associatedshackles may follow a linear path or a path which includes bends. Thepaths and/or the tunnel 2 and/or the pre/post treatment tunnels mayalternatively be any other suitable shape such as arcuate. The pre andpost treatment tunnels may be provided with any suitable equipment fortreating the carcasses as they pass through the tunnels. In particularthe pre and post treatment tunnels may be equipped with nozzles forspraying a cryogenic liquid into the tunnels. In a preferred embodiment,developed gas from the main treatment tunnel 2 will be fed into the preand/or post treatment tunnels to control the atmosphere and temperaturetherein. In one example the pre-treatment tunnel may be used topre-chill the carcasses before they enter the main treatment tunnel 2,and the post treatment tunnel may be used to raise the temperature ofthe carcasses exiting the main treatment tunnel 2. A heater may beprovided in either of the pre or post treatment tunnels to control thetemperature within the tunnels. Alternatively or additionally, theatmosphere/temperature may be controlled in the tunnels by theintroduction of the same/another gas (in liquid or gaseous form).

In a further alternative embodiment of the invention, the tunnel 2 asshown in FIG. 3 may be adapted to include pre and post treatment zones.For example the upstream portion of the tunnel 2 may be a pre-treatmentzone, the middle portion of the tunnel 2 the main treatment zone and thedownstream portion of the tunnel 2 the post treatment zone. Theintroduction of the liquid cryogen via nozzles 46 may be adapted asnecessary depending on desired flow rates, temperatures etc. Additionaltreatment equipment such as gas injection nozzles, fans, heaters,baffles, internal walls etcetera may be included in the pre and posttreatment zones as desired. In particular, internal walls may be used toseparate treatment zones within the tunnel 2. In the case of a tunnelhaving a monorail conveyor 22 following a straight path, the internalwalls may be similar to end was 10, 12 in that they have an openingthere through to allow the passage of the monorail conveyor 22, shacklesand carcasses. In the case of an S or U shaped monorail conveyor 22, thezones may be separated by internal walls or baffles which run parallelto the side walls 14, 16. Such walls/baffles may include openings toallow the passage of the monorail conveyor 22, shackles and carcasses.Alternatively, the walls/baffles may not extend along the entire lengthof the tunnel 2 thus providing space at the end of the wall/baffle toallow the monorail conveyor 22, shackles and carcasses to pass the endof the wall or baffle. In the case that walls or baffles are usedbetween sections of a U or shaped conveyor 22 additional spray bars 40may be used to ensure treatment is possible along the entire path of theconveyor 22. In the In the case of a U or S-shaped conveyor 22, spraybars 40 may optionally be provided so that, in use, only one side of thecarcasses are treated at any one time. For example, in the case of aU-shaped conveyor 22, spray bars 40 may be provided so that one side ofthe carcasses are treated along the first section of conveyor 22, andthe other side of the carcasses are treated along the second section ofthe conveyor 22. In this case, the nozzles 46 of the spray bars 40 wouldall face in the same direction. A similar arrangement may be used for anS-shaped conveyor 22 as desired. If desired, spray bars 40 may also bearranged in the tunnel 2 so that liquid cryogen may be sprayed uptowards the carcasses from the vicinity of the floor 6, or down onto thecarcasses from the roof 8.

The conveyor 22 may alternatively follow a wavy path, preferably withshallow curves. This arrangement may be useful for shortening the lengthof the tunnel 2 and changing the orientation of the carcasses as theypass through the tunnel, thereby changing the part of the carcassesdirected towards the nozzles 46. This in turn may allow a more thoroughtreatment of the carcasses by presenting parts of the carcasses towardsthe nozzles 46 that might otherwise be “hidden” from the cryogenicgas/mist. Such a path may for example be described by the equationy=a·sin (b·x), where y is the amplitude in metres of a sine wavedescribing the path of the conveyor 22, x is the distance along thelength of the tunnel 2 in metres, a is the desired maximum amplitude ofthe sine wave function, and b is a constant determining the wavelengthof the sine function. A suitable sine function may be y=0.1 sin (15x).This would give an amplitude of 0.1 m and a wavelength of 24 m. Anotherexample might be y=0.2 sin (36x) giving an amplitude of 0.2 m and awavelength of 10 m. It will be understood that these are examples onlyand that the monorail conveyor 22 may follow any other wavy pattern asdesired.

In order to capitalise on the cooling potential of the liquid cryogenused in the pre, post or main treatment tunnel(s), it is envisaged thatdeveloped gas (developed from the evaporating liquid cryogen) may beused in an upstream or downstream process as appropriate. One such useis to feed the developed cold gas to the chiller in which, or afterwhich, the tunnel(s) reside. In the case of liquid air, the developedgas may be fed directly into the chiller as a breathable atmosphere willbe maintained in the chiller. For other gases, such as nitrogen forexample, it may not be possible to feed the developed gas directly backto the chiller as this may be detrimental to the breathability of theatmosphere in the chiller. In this case, the developed gas may be fedthrough a heat exchanger which resides within the chiller. If necessary,the developed gas may be treated or scrubbed before it is used in anyother upstream or downstream processes.

It is also considered to be within the scope of the invention to use thetreatment tunnel(s) for any other type of carcass treatment which issuitable for use in a continuous in-line process. Such treatments mayinclude, for example, lactic acid treatment, steam wash, water spray,ultra violet, infra red, ozone or any combination thereof.

1. A tunnel for in-line anti-bacterial treatment of plucked poultrycarcasses (or other animal carcasses), comprising a chilling substanceselected from the group consisting of a cryogenic liquid and cold gas ata temperature below 0° C. in the tunnel, the tunnel having an entranceand an exit for the carcasses and a monorail conveyor extending throughthe tunnel from the entrance to the exit along which carcass suspensionshackles are able to pass.
 2. The tunnel according to claim 1, whereinthe monorail conveyor follows a path which reverses direction at leastonce.
 3. The tunnel according to claim 1, wherein the monorail conveyorfollows a path which reverses direction at least twice.
 4. The tunnelaccording to claim 1, wherein the monorail conveyor follows a wavy path.5. The tunnel according to claim 1, further comprising an array ofnozzles disposed in the tunnel for spraying the cryogenic liquid intothe tunnel.
 6. The tunnel according to claim 5, further comprising aplurality of fans disposed in the tunnel for moving cold gas within thetunnel.
 7. The tunnel according to claim 6, wherein at least one of theplurality of fans are directed for providing gas laterally relative to apath taken by the poultry carcasses through the tunnel.
 8. The tunnelaccording to claim 6, wherein at least one of the plurality of fanscomprise impingement fans.
 9. The tunnel according to claim 6, whereinthe array of nozzles are arranged to introduce droplets of the cryogenicliquid into cold gas being directed by the plurality of fans at thecarcasses.
 10. The tunnel according to claim 6, wherein the array ofnozzles are arranged to direct droplets of the cryogenic liquid toimpinge on the carcasses.
 11. The tunnel according to claim 2, in whicheach length of direction of the path followed by the carcasses comprisesa row of spray nozzles each spray nozzle being adapted to direct thecryogenic liquid at the carcasses.
 12. The tunnel according to claim 11,wherein each of the spray nozzles points in the same direction.
 13. Thetunnel according to claim 1, wherein the tunnel comprises at least oneoutlet port for extraction of gas from the tunnel.
 14. The tunnelaccording to claim 1, wherein the tunnel is arranged to provide atreatment and at least one of a pre-treatment and a post-treatment,wherein the treatment is along a portion of a path along which thecarcasses move, and the at least one of the pre and post treatment isalong another portion of the path along which the carcasses move. 15.The tunnel according to claim 14, wherein the tunnel is arranged toprovide the pre-treatment, the treatment and the post-treatment insequence.
 16. An apparatus for handling carcasses of poultry (or otheranimals) for anti-bacterial treatment, comprising: a tunnel comprising achilling substance selected from the group consisting of a cryogenicliquid and cold gas at a temperature below 0° C. in the tunnel, thetunnel having an entrance and an exit for the carcasses and a monorailconveyor extending through the tunnel from the entrance to the exitalong which carcass suspension shackles are able to pass; apre-treatment tunnel located upstream of the tunnel; and apost-treatment tunnel located down stream of the tunnel, wherein thepre-treatment tunnel and the post-treatment tunnel each comprise anentrance and an exit for the carcasses, and the monorail conveyorextends from at least the entrance of the pre-treatment tunnel to theexit of the post-treatment tunnel along which the carcass suspensionshackles are able to pass.
 17. The apparatus according to claim 16,wherein at least one of the pre-treatment tunnel and the post-treatmenttunnel are arranged to be supplied with at least one of developed gasand the liquid cryogen from the tunnel.
 18. The apparatus according toclaim 16, wherein at least a portion of said apparatus is located withina chiller of a processing plant.
 19. The apparatus according to claim18, wherein the tunnel is arranged to supply developed gas from thetunnel to the chiller or optionally to a heat exchanger located withinthe chiller.